Self-raising window covering

ABSTRACT

The present invention relates to a self-raising window covering and a control mechanism for the window covering. In particular, the window covering includes a drive unit, such as constant force spring, that is adapted to apply a substantially constant rotational force on the drive axle. A cord winding assembly is coaxially mounted on the drive axle, and includes at least one winding drum operatively connected to a second end of the raising cord and having a tapered portion, as well as a rotatable positioning member for moving the cord winding assembly laterally along the drive axle upon rotation of the positioning member. The cord winding assembly is adapted to translate the rotational force on the drive axle to a raising force on the raising cord, wherein the raising force is greater than a downward force exerted by the shade element and bottom rail throughout the range of opening and closing. A clutch member or locking member is also operatively connected with the axle and adapted to releasably lock the drive axle in a desired position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patent application Ser. No. 11/880,000, filed on Jul. 19, 2007, which is incorporated herein by reference.

FIELD OF INVENTION

The present invention relates to a window covering that may be raised without the need to apply a force to either a control mechanism or the window covering itself as the window covering is opened. In particular, the present invention relates to a window covering having a control mechanism configured to exert an upward force on the light blocking element and bottom element that is of sufficient magnitude to raise the light blocking element and bottom rail without additional force being applied by the user during raising. The control mechanism selectively raises the window bottom element and portions of the window covering, and may be actuated by a downward force applied to the bottom element by the user.

BACKGROUND OF THE INVENTION

Window shades and coverings are found in many applications and used to regulate the amount of light entering a room, and to provide aesthetic appeal to a decor. Such window shades and coverings take many forms, including roller shades, Roman shades, Venetian blinds, and cellular shades. Conventional cellular or pleated shades utilize cord locks or a transmission mechanism to raise, lower and position the window covering in a desired position. With window coverings utilizing a cord lock, cords run up through the folded fabric, across the inside of a head rail and exit through a locking mechanism. Other cellular shades include a transmission mechanism and a continuous loop cord that is pulled by a user to raise and lower the window shade. Roman shades and Venetian blinds also tend to include raising cords that are secured to a lower bar or bottom rail.

There are some disadvantages to these designs. Cords present the potential hazard of a child getting caught in or strangled by the exposed control cord. Cords also tend to distract from the aesthetics of a window covering in that they extend along the face of the window covering and, when the window shade is opened, must either be wrapped on a hook or just left on the floor. With window coverings that utilize cord locks, the cords also experience substantial wear due to friction against surfaces as a result of raising and lowering of the window covering.

Other window coverings include common roller shades, which operate in the absence of a cord. These roller shades include a wound torsion-spring retraction mechanism in combination with a clutch or locking mechanism mounted with a roller onto which the shade is rolled and collected. In operation, a roller shade is pulled down by a user to a desired location, where it is locked in place by the clutch or locking mechanism. To unlock and release the shade so that it may be raised, the user typically pulls on a bottom rail of the shade, extending the shade sufficiently to disengage the internal clutch or locking mechanism within. When the clutch or locking mechanism is disengaged and the user releases the shade, the shade is retracted using the torsion-spring driven retraction mechanism. Known roller shades, however, are only operable with flat shade material which rolls up neatly into a confined location.

The mechanism utilized in such roller shades is not compatible with other window coverings, such as cellular shades, Venetian blinds, and Roman shades. As roller shades are raised, the amount of shade being lifted decreases such that a constant force torsional spring member is capable of applying the necessary winding or upward force throughout the opening range. By contrast, a similar lifting mechanism is typically unsuitable in cellular shades, Venetian blinds, and Roman shades. In these types of window coverings the light blocking material is typically gathered by raising a bottom member, such as a bottom rail, and increasing amounts of weight are gathered on the bottom member as the window covering is raised. The reason for this is that the shade material or light blocking element increasingly stacks on the bottom rail as the bottom rail rises, which increases the load on the lifting mechanism.

In order to address this increasing weight, very strong torsional springs have been used to accommodate the maximum weight of the shade. One drawback to this approach, however, is that the rate at which the window covering is retracted may be too fast and uncontrolled. One attempt to address this problem is found in U.S. Pat. No. 6,666,252, issued to Welfonder. This patent teaches the use of a fluid brake to control the rate at which the raising cords are retracted throughout the raising process. Another approach that has been used is shown in U.S. Pat. No. 6,056,036, issued to Todd, which employs a mechanical friction member to continuously slow the rate of retraction. One problem with these approaches has been that the spring utilized exerts a force that is difficult for a user to overcome when attempting to lower the shade. Excessive pulling force by the user often results in damage to the window covering.

Alternatively, variable force springs have been used. Such variable force springs are substantially more complicated in use and manufacture.

Therefore, there is a need for a window covering raising mechanism for window coverings such as Venetian blinds, cellular shades and Roman shades that is self-raising and overcomes the foregoing problems.

SUMMARY OF THE INVENTION

The present invention relates to a self-raising window covering and a control mechanism for the window covering. In particular, the window covering is a self-raising window covering that includes a head rail, a light blocking element, such as a cellular panel, blind slats, or Roman shade material, a bottom rail or bottom element, at least one raising cord operatively connected at a first end to the bottom rail or bottom element, and a control mechanism. The head rail may define an elongated channel wherein the control mechanism is disposed therein. In some embodiments, the control mechanism includes a drive shaft and a drive unit operatively connected with the drive shaft. The drive unit, which may be a constant force spring, is adapted to provide a substantially constant rotational force on the drive shaft.

At least one translation member is also provided in co-axial relation with the drive shaft. Typically, the number of translation members will be the same as the number of raising cords. However, in some instances, the translation member may be adapted to raised multiple cords. The translation member preferably includes at least one winding drum operatively connected to a second end of the raising cord and having a tapered portion. The translation member also includes a rotatable positioning member for moving the translation member laterally along the drive shaft upon rotation of the positioning member. In a preferred embodiment, the positioning member is a threaded tubular member connected to the winding drum. The translation member is adapted to translate the rotational force on the drive shaft to a raising force on the raising cord, wherein the raising force is greater than a downward force exerted by the light blocking element and bottom rail throughout the range of opening and closing. In a preferred embodiment, the translation member is rotationally secured with the drive shaft by a hub member adapted to engage the translation member and the drive shaft. The hub member may be in a sliding relationship with the tapered portion of the translation member.

A clutch or locking or actuating member is also operatively connected with the axle and adapted to releasably lock the drive shaft in a desired position. In a preferred embodiment, the clutch or locking or actuating member comprises a spring member adapted to releasably secure the position of the drive shaft when in a tightened condition and to permit rotation of the drive shaft when in a relaxed condition. A reciprocator may also be disposed annularly about the drive shaft and adapted to selectively hold the spring member in the tightened and relaxed positions. An annular collar may also be secured with the drive shaft and connected with the spring member. In some embodiments, it may also be desired to include a brake unit engageable with the translation member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view, partly in cutaway, of a preferred embodiment of a window covering according to the present invention;

FIG. 2 is a exploded perspective view of the single spring coil drive unit of FIG. 1;

FIG. 3 is a side elevational cross section view of the single spring coil drive unit of FIG. 1;

FIG. 4 is a side elevational cross section view of an alternative single spring coil drive unit;

FIG. 5 is a side elevational cross section view of a double spring drive unit;

FIG. 6 is a side elevational cross section view of an alternative double spring drive unit;

FIG. 7 is an exploded perspective view of the translation member of FIG. 1;

FIG. 8A is a front elevational view of the window covering of FIG. 1 in a closed position and with the head rail in cross section;

FIG. 8B is a front elevational view of the window covering of FIG. 1 in a partially open position and with the head rail in cross section;

FIG. 9A is a perspective view of a preferred clutch member when the window covering is in a fully raised position;

FIG. 9B is a cross sectional view of the clutch member of FIG. 9A;

FIG. 10A is a perspective view of the clutch member of FIG. 9A as the user pulls down on the window covering;

FIG. 10B is a cross sectional view of the clutch member of FIG. 10A;

FIG. 11A is a perspective view of the clutch member of FIG. 9A as the user releases the window covering;

FIG. 11B is a cross sectional view of the clutch member of FIG. 11A;

FIG. 12A is a perspective view of the clutch member of FIG. 9A as the user pulls down on the window covering to release the clutch member;

FIG. 12B is a cross sectional view of the clutch member of FIG. 12A;

FIG. 13A is a perspective view of the clutch member of FIG. 9A as the window covering self-raises;

FIG. 13B is a cross sectional view of the clutch member of FIG. 13A;

FIG. 14 is a perspective view of an alterative embodiment of a window covering according to the present invention with a deceleration member;

FIG. 15A is a side elevational cross section view of the deceleration member of FIG. 14 disengaged from the translation member;

FIG. 15B is a side elevational cross section view of the deceleration member of FIG. 14 engaging the translation member; and

FIG. 15C is a side elevational cross section view of the deceleration member of FIG. 14 when the window covering is fully raised.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention disclosed herein is susceptible to embodiment in many different forms. Shown in the drawings and described in detail hereinbelow are preferred embodiments of the present invention. The present disclosure, however, is only an exemplification of the principles and features of the invention, and does not limit the invention to the illustrated embodiments.

Referring to FIG. 1, an embodiment of a self-raising window covering 10 according to the present invention is shown. A head rail 12 defining a channel is provided. A pair of drive units, such as spring units 14 and 16 are coaxially mounted about a drive axle 18. Also mounted on drive axle 16 are translation members 20 and 22. Each of translation members 20 and 22 includes a frustoconical winding drum 24 and 26, respectively. Raising cords 28 and 30, which are shown as wound on winding drums 24 and 26, are secured at an end to the winding drums 24 and 26. Each of the translation members 20 and 22 further comprise a threaded tubular member 32, 34. In this embodiment, a clutch or actuator 36 is also provided and co-axially mounted on the drive axle 18. Each of these components is discussed in greater detail below. Window covering 10 further includes a light blocking element, such as cellular shade material 38 and a bottom member, such as bottom rail 40. A relatively short length of cord 42 is also provided so that the user can pull down the window covering and, as will be discussed in further detail, release the clutch so that the window covering will retract itself.

Referring to FIG. 2, a preferred embodiment of the spring unit 14 is shown. The spring unit 14 comprises a spring casing 42, a spring axle 44, a constant force coil spring 46 and a cover 48. The coil spring 46 is secured with the spring axle 44, and is secured within the casing 42 and cover 48. With coil spring 46, a first end 50 of the spring 46 is secured to the spring axle 44, which is mounted on the drive axle 18 (FIG. 1). In this preferred embodiment, the coil spring provides sufficient rotational force to the drive axle and winding drums to raise the light blocking element and bottom rail. Other alternative embodiments of suitable spring units are shown in FIGS. 3-6.

For example, a spring unit 114 is shown in FIG. 3 as including a spring axle 144 and a spring member 146. The spring axle 144 is offset from the drive axle 118. A first end 150 of the spring member 146 is secured with the spring axle 144 and a second end 152 is secured with the drive axle 118 to impart a rotational force thereon. Another example of a suitable spring unit is shown in FIG. 4 as spring unit 214. This example is similar to the embodiment shown in FIG. 3 except that no spring axle is provided. Instead, a portion of spring member 246 coils about itself and an end 252 of the spring member 246 is secured to the drive axle 218. Still other suitable embodiments of spring units are shown in FIGS. 5 and 6. In FIG. 5, spring unit 314 includes a double spring coil member 346 which is secured to a drive axle 318 and to spring axles 344 and 345. In FIG. 6, a double spring coil member 446 is connected to drive axle 418, but does not include spring axles. Although each of the embodiments shown utilize a spring as the driving mechanism for the drive unit, it should be understood that any suitable mechanism for imparting a rotational force on a drive axle may be utilized.

Referring again to FIG. 1, the rotational force exerted upon a drive axle 18 causes the raising of the light blocking 38 by way of translation member 20 and 22. Further details on a preferred embodiment of a translation member is provided with reference to FIG. 7.

Translation member 20 is mounted co-axially with the drive shaft (not shown), and includes a winding drum 24 and a rotational positioning member, such as threaded tubular member 32. The translation member 20 is preferably mounted to the drive axle by way of a hub member, such as adapter 60. The winding drum 24 may be tapered and is preferably frustoconical in shape, and may include striations or grooves. An end of the raising cord (not shown) is secured towards the larger diameter end 62 of the winding drum 24 such that as the cord is wound, the raising cord is wrapped around increasingly narrower portions of the winding drum 24. The translation member is mounted within the head rail 12 (FIG. 1) by way of frame 64, which includes rollers 66. Rollers 66 engage threaded tubular member 32, and are held in position by bracket 68.

Referring to FIGS. 8A and 8B, the raising of the window covering is shown. When the window covering is fully closed, as shown in FIG. 8A, the raising cord 28 is fully extended and connected to the winding drum 24 at a wider portion thereof. As the bottom rail rises, the threaded tubular member 32 causes the translation member to move laterally within the head rail 12 such that the raising cord extends substantially straight down from the winding drum 24, as shown in FIG. 8B.

As the spring units 14 and 16 raise the bottom rail 40 and stack the light blocking element 38 on the bottom rail 40, the total weight being raised increases. The load of the springs is described with reference to one of the spring units. The load of the spring unit 14 can be approximated as the force F relative to the drive axle as being equal to the product of the suspended weight W, which includes the weight of the bottom rail plus the amount of panel stacked thereon, by a winding radius R of the winding drum 24. As the bottom rail rises, W increases while R decreases. Because of the tapered winding drum 24, the force of the spring unit 14 translated to an upward force on the raising cord 28 will vary slightly so that the constant force spring 46 (FIG. 2) can fully raise the bottom rail 40 and light blocking element 38. In order to lower the window covering, a user exerts an approximately constant pulling force regardless of the position in height of the window covering. When the window covering is raised, the total weight stacked on the bottom rail is at its maximum. As the user pulls down on the bottom rail 40 or cord 42, the contribution to the force needed to overcome the upward force of the spring units 14 and 16 from the weight of the bottom rail 40 and light blocking element 38 decreases. However, the effective pulling force is increased due to the greater moment arm. As such, the user does not need to exert as much force as would be required with a cylindrical winding drum.

As discussed, the drive units are configured to provide a force sufficient to raise the bottom rail 40 and light blocking element 38 regardless of the current position of the window covering. Accordingly, a clutch member or actuator 36 is also provided in order to lock the window covering in a desired position. Clutch member 36 is mounted with the drive axle 18 and is configured to unlock the drive axle 18 as the user pulls down the bottom rail 40, and to lock the drive axle 18 when the user releases the bottom rail 40 at the desired height. When the user pulls down slightly on the bottom rail again, the clutch disengages and allows the bottom rail 40 to be raised by the spring units 14 and 16. Referring to FIGS. 9A and 9B, the clutch member 36 includes a casing 70 with protrusions 72 and 74 projecting therefrom. A collar 76 rotating with the drive axle 18 is provided, which reciprocates axially along the drive axle 18. A reciprocator 78 is co-axially mounted over collar 76 and is movable both rotatably and axially therewith. A spring 80 having a first end 82 and a second end 84 is provided between collar 76 and reciprocator 78.

FIGS. 9A and 9B show the clutch 76 when the window covering 10 is in a fully raised position. Spring 80 is in a relaxed condition with second end 84 in an abutting relationship with protrusion 74. As shown in FIGS. 10A and 10B, when the user pulls on the bottom rail (not shown), a clockwise rotation (as shown) of the axle 18 and the collar 76 occurs and causes the second end 84 of the spring 80 to disengage from protrusion 74. Spring 80 tightens on collar 76 such that rotation of the collar 76 brings reciprocator 78 into abutment with protrusion 72 through contact at second end 84 of the spring 80. As the reciprocator 78 abuts against protrusion 72, the spring 80 relaxes again such that drive axle 18 may continue to rotate as the user pulls on the bottom rail. Referring to FIG. 11A and 11B, as the user releases the bottom rail at a desired height, spring 80 again tightens on collar 76. The drive axle 18, as urged by the spring units 14 and 16 (FIG. 1), rotates receiprocator 78 in a counterclockwise direction to a locking position. In this locking position, the spring 80 tightens to stop rotation of the drive axle 18. Referring to FIGS. 12A and 12B, as the user pulls down slightly on the bottom rail, a resulting clockwise rotation of the drive axle 18 and collar 76 causes the reciprocator 78 to disengage from the locking position. When the user releases the bottom rail as shown in FIGS. 13A and 13B, the spring units 14 and 16 cause the drive axle 18 to rotate in a counterclockwise direction to bring second end 84 of the spring 80 into engagement with protrusion 74, and thereby loosening spring 80, which permits drive axle 18 to continue rotating and fully opening the window covering.

An alternative embodiment of the window covering according to the present invention is shown in FIG. 14. In most respects, this embodiment is the same as the ones previously discussed. Window covering 510 includes a head rail 512 having a pair of spring units 514 and 516 mounted with a drive axle 518 mounted therein. Translation members 520 and 522 are also provided. Raising cords 528 and 530 pass through light blocking element 538 and are connected with bottom rail 540. In addition, a deceleration member 550 is provided. Deceleration members 550 is engageable with the translation member 522 to slow down the rise of the bottom rail as it approaches the head rail.

The preferred embodiment of the deceleration member 520 is shown in FIGS. 15A-15C. In the position of FIG. 15A, the translation member is disengaged from the deceleration member 550. As the winding cord 526 is wound on winding drum 24, the translation member 522 moves towards the deceleration member 550. As the translation member engages with the deceleration member 550 as shown in FIG. 15B, the rotation of the winding drum 526 causes a plate 552 of the deceleration member to rotate. The plate 552 is operative connected to an axle sleeve 554. Axle sleeve 554 is in contact with an oil liquid contained inside a housing 556 and is configured to provide rotational movement resistance within the oil liquid. For example, protrusions or fins may be provided on the axle sleeve 554. The rate at which the bottom rail is raised by the spring units 514 and 516 is slowed as the bottom rail reaches the head rail so that the bottom rail more smoothly stops at a fully opened position.

The foregoing descriptions are to be taken as illustrative, but not limiting. Still other variants within the spirit and scope of the present invention will readily present themselves to those skilled in the art. 

1. A window covering comprising: a head rail; a shade element including a top end and a bottom end, wherein the top end is secured with the head rail, and the shade element is vertically suspended from the head rail and suspended at a stationary first position; a bottom element secured with the bottom end of the shade element; a raising member connecting a control mechanism and the bottom element; the control mechanism including a drive unit that exerts a raising force in a first direction, the raising force being selectively communicated to the raising member and is sufficient to raise the bottom element from the first position to a second position and to stack increasing portions of the shade element on the bottom element, the control mechanism further including an actuator having a locked condition and a release condition such that when in the locked condition the actuator counteracts application of the raising force on the raising member, and when the actuator is in the release condition the raising force is communicated to the raising member to raise the bottom element; and the actuator is moved from the locked condition to the release condition by communication of a second force to the drive unit, the second force being opposite in direction to the raising force in the first direction.
 2. The window covering of claim 1, wherein the bottom element is stationary in the first position and the actuator is in the locked condition.
 3. The window covering of claim 1, wherein the bottom element is movable from a position vertically higher than the first position to the first position by a downward force on the bottom element, wherein after release of the downward force the actuator switch member is in the locked position.
 4. The window covering of claim 1, wherein: the raising member is a cord element having a distal end connected with the bottom element; the control mechanism further comprises a cord winding assembly configured to wind and unwind the cord element; the drive unit continuously applies a spring force for rotating the cord winding assembly in the first direction that winds the cord element; and the actuator is a clutch operable to selectively lock rotation of the cord winding assembly.
 5. The window covering of claim 4, wherein the clutch member permits rotation of the cord winding assembly in a direction for unwinding the cord element when a downward force is applied on the bottom element.
 6. The window covering of claim 4, wherein the drive unit continuously applies the spring force on a drive axle coupled with the clutch member and the cord winding assembly.
 7. The window covering of claim 6, wherein the clutch member selectively locks rotation of the drive axle against the spring force of the drive spring unit.
 8. The window covering of claim 1, wherein the shade element includes a collapsible structure.
 9. A window covering comprising: a head rail; a shade element vertically suspended from the head rail; a bottom element secured with a bottom end of the shade element, the bottom element being suspended from the head rail at a first position; and a control mechanism operatively connected to the bottom element by a raising member, wherein the control member selectively retracts the raising member and raises the bottom element from a first position to a second position in response to a downward displacement of the bottom element from the first position sufficient to disengage an actuator, and wherein increasing portions of the shade element are stacked on the bottom element as the bottom element is raised.
 10. The window covering of claim 9, wherein the raising member is a cord, and wherein the control mechanism comprises: a spring unit; a cord winding assembly coupled with the bottom element via the cord; and the actuator is a clutch member configured to block rotation of the cord winding assembly when the bottom element is in the first position, and enable rotation of the cord winding assembly in response to the downward displacement of the bottom element from the first position.
 11. The window covering of claim 10, wherein the spring unit continuously applies a spring force to rotate the cord winding assembly in a first direction that winds the cord element.
 12. The window covering of claim 10, wherein the clutch member permits rotation of the cord winding assembly in a second direction for unwinding the cord element when a downward pulling force is applied on the bottom element.
 13. The window covering of claim 10, wherein the clutch member and the cord winding assembly are coupled with a drive axle.
 14. The window covering of claim 13, wherein the spring unit applies the spring force on the drive axle.
 15. The window covering of claim 14, wherein the clutch member selectively blocks rotation of the drive axle against the spring force.
 16. The window covering of claim 9, wherein the shade element includes a collapsible structure.
 17. A method of operating a window covering, wherein the window covering comprises a shade element vertically suspended from a head rail, a bottom element secured with a bottom end of the shade element, and a control mechanism adapted to apply a spring force in a first direction to selectively raise the bottom element and to stack increasing portions of the shade element on the bottom element, the method comprising: applying a downward force on the bottom element and moving the bottom element from a stationary first position to a release position lower than the first position such that the downward force is communicated to the control mechanism and acts in an opposite direction to the spring force in the first direction; and discontinuing application of the downward force on the bottom element when the bottom element is at the release position; and permitting the spring force of the control mechanism to raise the bottom element free of a user applied upward force on the bottom element and such that at least a portion of the shade element is stacked on the bottom element.
 18. The method of claim 17, wherein the shade element includes a collapsible structure.
 19. The method of claim 17, further comprising applying a downward force on the bottom element after permitting the spring force of the control mechanism to raise the bottom element and causing the control mechanism to block further raising of the bottom element. 